Perpendicular magnetic tunnel junction having improved reference layer stability
A magnetic data recording element for magnetic random access memory data recording. The magnetic data recording element includes a magnetic tunnel junction element that includes a magnetic reference layer, a magnetic free layer and a non-magnetic barrier layer located between the non-magnetic reference layer and the magnetic free layer. The magnetic reference layer includes a layer of Hf that causes the magnetic reference layer to have an increased perpendicular magnetic anisotropy. This increased perpendicular magnetic anisotropy improves reliability and stability of the magnetic data recording element by preventing loss of magnetic orientation of the magnetic reference layer such as during high writing current conditions.
1. A magnetic random access memory element comprising:
a magnetic reference layer;
a magnetic free layer; and
a non-magnetic barrier layer, located between the magnetic reference layer and the magnetic free layer;
the magnetic reference layer comprising at least one magnetic layer and a layer of Hf;
wherein the layer of Hf is located between the at least one magnetic layer and the non-magnetic barrier layer or the layer of Hf is located within the magnetic reference layer between a pair of magnetic layers.
2. The magnetic random access memory element as in claim 1 , wherein the layer of Hf contacts the non-magnetic barrier layer.
3. The magnetic random access memory element as in claim 1 , wherein the layer of Hf is part of a bi-layer structure that includes the layer of Hf and a layer of Mg—O.
4. The magnetic random access memory element as in claim 3 , wherein the layer of Mg—O has a thickness that is no greater than 3 Angstroms.
5. The magnetic random access memory element as in claim 1 , wherein the layer of Hf has a thickness that is not greater than 3 Angstroms.
6. The magnetic random access memory element as in claim 1 , wherein the layer of Hf has a thickness of 1 Angstrom.
7. The magnetic random access memory element as in claim 1 , wherein the magnetic reference layer further comprises a second layer of Hf.
8. The magnetic random access memory element as in claim 1 , wherein the reference layer comprises a plurality of layers of Hf at different locations within the magnetic reference layer.
9. The magnetic random access memory element as in claim 1 , wherein the reference layer further comprises, a separation layer located between magnetic layers.
10. The magnetic random access memory element as in claim 9 , wherein the separation layer comprises Mo.
11. The magnetic random access memory element as in claim 1 , wherein the layer of Hf is located between first and second layers of CoFeB.
12. The magnetic random access memory element as in claim 1 , wherein the layer of Hf is located between a layer of CoFeB and a layer of MgO.
13. The magnetic random access memory element as in claim 1 , wherein the layer of Hf has is located between first and second magnetic layers and wherein the layer of Hf has is sufficiently thin to avoid breaking exchange coupling between the first and second magnetic layers.
14. The magnetic random access memory element as in claim 1 , wherein the layer of Hf is part of a bi-layer structure that includes the layer of Hf and a layer of Mo.
15. The magnetic random access memory element as in claim 14 , wherein the layer of Hf and a layer of Mo is located between two magnetic layers of CofeB.
16. A magnetic random access memory element comprising:
a magnetic reference layer;
a magnetic free layer; and
a non-magnetic barrier layer, located between the magnetic reference layer and the magnetic free layer;
the magnetic reference layer comprising:
first and second magnetic layers;
a separation layer located between the first and second layers; and
a layer of Hf.
17. The magnetic random access memory element as in claim 16 , wherein the layer of Hf is located between the second magnetic layer and the non-magnetic barrier layer.
18. The magnetic random access memory element as in claim 16 wherein the magnetic reference layer structure further comprises a third magnetic layer, and wherein the layer of Hf is located between the second and third magnetic layers.
19. The magnetic random access memory element as in claim 17 , wherein the layer of Hf is part of a bi-layer structure that includes the layer of Hf and a layer of MgO.
20. A magnetic random access memory system, comprising:
a plurality of magnetic memory elements; and
circuitry configured to write data to the plurality of magnetic memory elements and read data from the plurality of magnetic memory elements;
each of the plurality of magnetic memory elements further comprising:
a magnetic reference layer;
a magnetic free layer; and
a non-magnetic barrier layer, located between the magnetic reference layer and the magnetic free layer; and
the magnetic reference layer comprising at least one magnetic layer and a layer of Hf;
wherein the layer of Hf is located between the at least one magnetic layer and the non-magnetic barrier layer or the layer of Hf is located within the magnetic reference layer between a pair of magnetic layers.